/**
 * @author mrdoob / http://mrdoob.com/
 */
let THREE = require("three");


// o object_name | g group_name
var object_pattern = /^[og]\s*(.+)?/;
// mtllib file_reference
var material_library_pattern = /^mtllib /;
// usemtl material_name
var material_use_pattern = /^usemtl /;
// usemap map_name
var map_use_pattern = /^usemap /;

function ParserState() {

    var state = {
        objects: [],
        object: {},

        vertices: [],
        normals: [],
        colors: [],
        uvs: [],

        materialLibraries: [],

        startObject: function (name, fromDeclaration) {

            // If the current object (initial from reset) is not from a g/o declaration in the parsed
            // file. We need to use it for the first parsed g/o to keep things in sync.
            if (this.object && this.object.fromDeclaration === false) {

                this.object.name = name;
                this.object.fromDeclaration = (fromDeclaration !== false);
                return;

            }

            var previousMaterial = (this.object && typeof this.object.currentMaterial === 'function' ? this.object.currentMaterial() : undefined);

            if (this.object && typeof this.object._finalize === 'function') {

                this.object._finalize(true);

            }

            this.object = {
                name: name || '',
                fromDeclaration: (fromDeclaration !== false),

                geometry: {
                    vertices: [],
                    normals: [],
                    colors: [],
                    uvs: []
                },
                materials: [],
                smooth: true,

                startMaterial: function (name, libraries) {

                    var previous = this._finalize(false);

                    // New usemtl declaration overwrites an inherited material, except if faces were declared
                    // after the material, then it must be preserved for proper MultiMaterial continuation.
                    if (previous && (previous.inherited || previous.groupCount <= 0)) {

                        this.materials.splice(previous.index, 1);

                    }

                    var material = {
                        index: this.materials.length,
                        name: name || '',
                        mtllib: (Array.isArray(libraries) && libraries.length > 0 ? libraries[libraries.length - 1] : ''),
                        smooth: (previous !== undefined ? previous.smooth : this.smooth),
                        groupStart: (previous !== undefined ? previous.groupEnd : 0),
                        groupEnd: -1,
                        groupCount: -1,
                        inherited: false,

                        clone: function (index) {

                            var cloned = {
                                index: (typeof index === 'number' ? index : this.index),
                                name: this.name,
                                mtllib: this.mtllib,
                                smooth: this.smooth,
                                groupStart: 0,
                                groupEnd: -1,
                                groupCount: -1,
                                inherited: false
                            };
                            cloned.clone = this.clone.bind(cloned);
                            return cloned;

                        }
                    };

                    this.materials.push(material);

                    return material;

                },

                currentMaterial: function () {

                    if (this.materials.length > 0) {

                        return this.materials[this.materials.length - 1];

                    }

                    return undefined;

                },

                _finalize: function (end) {

                    var lastMultiMaterial = this.currentMaterial();
                    if (lastMultiMaterial && lastMultiMaterial.groupEnd === -1) {

                        lastMultiMaterial.groupEnd = this.geometry.vertices.length / 3;
                        lastMultiMaterial.groupCount = lastMultiMaterial.groupEnd - lastMultiMaterial.groupStart;
                        lastMultiMaterial.inherited = false;

                    }

                    // Ignore objects tail materials if no face declarations followed them before a new o/g started.
                    if (end && this.materials.length > 1) {

                        for (var mi = this.materials.length - 1; mi >= 0; mi--) {

                            if (this.materials[mi].groupCount <= 0) {

                                this.materials.splice(mi, 1);

                            }

                        }

                    }

                    // Guarantee at least one empty material, this makes the creation later more straight forward.
                    if (end && this.materials.length === 0) {

                        this.materials.push({
                            name: '',
                            smooth: this.smooth
                        });

                    }

                    return lastMultiMaterial;

                }
            };

            // Inherit previous objects material.
            // Spec tells us that a declared material must be set to all objects until a new material is declared.
            // If a usemtl declaration is encountered while this new object is being parsed, it will
            // overwrite the inherited material. Exception being that there was already face declarations
            // to the inherited material, then it will be preserved for proper MultiMaterial continuation.

            if (previousMaterial && previousMaterial.name && typeof previousMaterial.clone === 'function') {

                var declared = previousMaterial.clone(0);
                declared.inherited = true;
                this.object.materials.push(declared);

            }

            this.objects.push(this.object);

        },

        finalize: function () {

            if (this.object && typeof this.object._finalize === 'function') {

                this.object._finalize(true);

            }

        },

        parseVertexIndex: function (value, len) {

            var index = parseInt(value, 10);
            return (index >= 0 ? index - 1 : index + len / 3) * 3;

        },

        parseNormalIndex: function (value, len) {

            var index = parseInt(value, 10);
            return (index >= 0 ? index - 1 : index + len / 3) * 3;

        },

        parseUVIndex: function (value, len) {

            var index = parseInt(value, 10);
            return (index >= 0 ? index - 1 : index + len / 2) * 2;

        },

        addVertex: function (a, b, c) {

            var src = this.vertices;
            var dst = this.object.geometry.vertices;

            dst.push(src[a + 0], src[a + 1], src[a + 2]);
            dst.push(src[b + 0], src[b + 1], src[b + 2]);
            dst.push(src[c + 0], src[c + 1], src[c + 2]);

        },

        addVertexPoint: function (a) {

            var src = this.vertices;
            var dst = this.object.geometry.vertices;

            dst.push(src[a + 0], src[a + 1], src[a + 2]);

        },

        addVertexLine: function (a) {

            var src = this.vertices;
            var dst = this.object.geometry.vertices;

            dst.push(src[a + 0], src[a + 1], src[a + 2]);

        },

        addNormal: function (a, b, c) {

            var src = this.normals;
            var dst = this.object.geometry.normals;

            dst.push(src[a + 0], src[a + 1], src[a + 2]);
            dst.push(src[b + 0], src[b + 1], src[b + 2]);
            dst.push(src[c + 0], src[c + 1], src[c + 2]);

        },

        addColor: function (a, b, c) {

            var src = this.colors;
            var dst = this.object.geometry.colors;

            dst.push(src[a + 0], src[a + 1], src[a + 2]);
            dst.push(src[b + 0], src[b + 1], src[b + 2]);
            dst.push(src[c + 0], src[c + 1], src[c + 2]);

        },

        addUV: function (a, b, c) {

            var src = this.uvs;
            var dst = this.object.geometry.uvs;

            dst.push(src[a + 0], src[a + 1]);
            dst.push(src[b + 0], src[b + 1]);
            dst.push(src[c + 0], src[c + 1]);

        },

        addUVLine: function (a) {

            var src = this.uvs;
            var dst = this.object.geometry.uvs;

            dst.push(src[a + 0], src[a + 1]);

        },

        addFace: function (a, b, c, ua, ub, uc, na, nb, nc) {

            var vLen = this.vertices.length;

            var ia = this.parseVertexIndex(a, vLen);
            var ib = this.parseVertexIndex(b, vLen);
            var ic = this.parseVertexIndex(c, vLen);

            this.addVertex(ia, ib, ic);

            if (this.colors.length > 0) {

                this.addColor(ia, ib, ic);

            }

            if (ua !== undefined && ua !== '') {

                var uvLen = this.uvs.length;
                ia = this.parseUVIndex(ua, uvLen);
                ib = this.parseUVIndex(ub, uvLen);
                ic = this.parseUVIndex(uc, uvLen);
                this.addUV(ia, ib, ic);

            }

            if (na !== undefined && na !== '') {

                // Normals are many times the same. If so, skip function call and parseInt.
                var nLen = this.normals.length;
                ia = this.parseNormalIndex(na, nLen);

                ib = na === nb ? ia : this.parseNormalIndex(nb, nLen);
                ic = na === nc ? ia : this.parseNormalIndex(nc, nLen);

                this.addNormal(ia, ib, ic);

            }

        },

        addPointGeometry: function (vertices) {

            this.object.geometry.type = 'Points';

            var vLen = this.vertices.length;

            for (var vi = 0, l = vertices.length; vi < l; vi++) {

                this.addVertexPoint(this.parseVertexIndex(vertices[vi], vLen));

            }

        },

        addLineGeometry: function (vertices, uvs) {

            this.object.geometry.type = 'Line';

            var vLen = this.vertices.length;
            var uvLen = this.uvs.length;

            for (var vi = 0, l = vertices.length; vi < l; vi++) {

                this.addVertexLine(this.parseVertexIndex(vertices[vi], vLen));

            }

            for (var uvi = 0, l = uvs.length; uvi < l; uvi++) {

                this.addUVLine(this.parseUVIndex(uvs[uvi], uvLen));

            }

        }

    };

    state.startObject('', false);

    return state;

}

//

function OBJLoader(manager) {

    THREE.Loader.call(this, manager);

    this.materials = null;

}

OBJLoader.prototype = Object.assign(Object.create(THREE.Loader.prototype), {

    constructor: OBJLoader,

    load: function (url, onLoad, onProgress, onError) {

        var scope = this;

        var loader = new THREE.FileLoader(scope.manager);
        loader.setPath(this.path);
        loader.load(url, function (text) {

            onLoad(scope.parse(text));

        }, onProgress, onError);

    },

    setMaterials: function (materials) {

        this.materials = materials;

        return this;

    },

    parse: function (text) {

        console.time('OBJLoader');

        var state = new ParserState();

        if (text.indexOf('\r\n') !== -1) {

            // This is faster than String.split with regex that splits on both
            text = text.replace(/\r\n/g, '\n');

        }

        if (text.indexOf('\\\n') !== -1) {

            // join lines separated by a line continuation character (\)
            text = text.replace(/\\\n/g, '');

        }

        var lines = text.split('\n');
        var line = '', lineFirstChar = '';
        var lineLength = 0;
        var result = [];

        // Faster to just trim left side of the line. Use if available.
        var trimLeft = (typeof ''.trimLeft === 'function');

        for (var i = 0, l = lines.length; i < l; i++) {

            line = lines[i];

            line = trimLeft ? line.trimLeft() : line.trim();

            lineLength = line.length;

            if (lineLength === 0) continue;

            lineFirstChar = line.charAt(0);

            // @todo invoke passed in handler if any
            if (lineFirstChar === '#') continue;

            if (lineFirstChar === 'v') {

                var data = line.split(/\s+/);

                switch (data[0]) {

                    case 'v':
                        state.vertices.push(
                            parseFloat(data[1]),
                            parseFloat(data[2]),
                            parseFloat(data[3])
                        );
                        if (data.length >= 7) {

                            state.colors.push(
                                parseFloat(data[4]),
                                parseFloat(data[5]),
                                parseFloat(data[6])
                            );

                        }
                        break;
                    case 'vn':
                        state.normals.push(
                            parseFloat(data[1]),
                            parseFloat(data[2]),
                            parseFloat(data[3])
                        );
                        break;
                    case 'vt':
                        state.uvs.push(
                            parseFloat(data[1]),
                            parseFloat(data[2])
                        );
                        break;

                }

            } else if (lineFirstChar === 'f') {

                var lineData = line.substr(1).trim();
                var vertexData = lineData.split(/\s+/);
                var faceVertices = [];

                // Parse the face vertex data into an easy to work with format

                for (var j = 0, jl = vertexData.length; j < jl; j++) {

                    var vertex = vertexData[j];

                    if (vertex.length > 0) {

                        var vertexParts = vertex.split('/');
                        faceVertices.push(vertexParts);

                    }

                }

                // Draw an edge between the first vertex and all subsequent vertices to form an n-gon

                var v1 = faceVertices[0];

                for (var j = 1, jl = faceVertices.length - 1; j < jl; j++) {

                    var v2 = faceVertices[j];
                    var v3 = faceVertices[j + 1];

                    state.addFace(
                        v1[0], v2[0], v3[0],
                        v1[1], v2[1], v3[1],
                        v1[2], v2[2], v3[2]
                    );

                }

            } else if (lineFirstChar === 'l') {

                var lineParts = line.substring(1).trim().split(" ");
                var lineVertices = [], lineUVs = [];

                if (line.indexOf("/") === -1) {

                    lineVertices = lineParts;

                } else {

                    for (var li = 0, llen = lineParts.length; li < llen; li++) {

                        var parts = lineParts[li].split("/");

                        if (parts[0] !== "") lineVertices.push(parts[0]);
                        if (parts[1] !== "") lineUVs.push(parts[1]);

                    }

                }
                state.addLineGeometry(lineVertices, lineUVs);

            } else if (lineFirstChar === 'p') {

                var lineData = line.substr(1).trim();
                var pointData = lineData.split(" ");

                state.addPointGeometry(pointData);

            } else if ((result = object_pattern.exec(line)) !== null) {

                // o object_name
                // or
                // g group_name

                // WORKAROUND: https://bugs.chromium.org/p/v8/issues/detail?id=2869
                // var name = result[ 0 ].substr( 1 ).trim();
                var name = (" " + result[0].substr(1).trim()).substr(1);

                state.startObject(name);

            } else if (material_use_pattern.test(line)) {

                // material

                state.object.startMaterial(line.substring(7).trim(), state.materialLibraries);

            } else if (material_library_pattern.test(line)) {

                // mtl file

                state.materialLibraries.push(line.substring(7).trim());

            } else if (map_use_pattern.test(line)) {

                // the line is parsed but ignored since the loader assumes textures are defined MTL files
                // (according to https://www.okino.com/conv/imp_wave.htm, 'usemap' is the old-style Wavefront texture reference method)

                console.warn('THREE.OBJLoader: Rendering identifier "usemap" not supported. Textures must be defined in MTL files.');

            } else if (lineFirstChar === 's') {

                result = line.split(' ');

                // smooth shading

                // @todo Handle files that have varying smooth values for a set of faces inside one geometry,
                // but does not define a usemtl for each face set.
                // This should be detected and a dummy material created (later MultiMaterial and geometry groups).
                // This requires some care to not create extra material on each smooth value for "normal" obj files.
                // where explicit usemtl defines geometry groups.
                // Example asset: examples/models/obj/cerberus/Cerberus.obj

                /*
                 * http://paulbourke.net/dataformats/obj/
                 * or
                 * http://www.cs.utah.edu/~boulos/cs3505/obj_spec.pdf
                 *
                 * From chapter "Grouping" Syntax explanation "s group_number":
                 * "group_number is the smoothing group number. To turn off smoothing groups, use a value of 0 or off.
                 * Polygonal elements use group numbers to put elements in different smoothing groups. For free-form
                 * surfaces, smoothing groups are either turned on or off; there is no difference between values greater
                 * than 0."
                 */
                if (result.length > 1) {

                    var value = result[1].trim().toLowerCase();
                    state.object.smooth = (value !== '0' && value !== 'off');

                } else {

                    // ZBrush can produce "s" lines #11707
                    state.object.smooth = true;

                }
                var material = state.object.currentMaterial();
                if (material) material.smooth = state.object.smooth;

            } else {

                // Handle null terminated files without exception
                if (line === '\0') continue;

                throw new Error('THREE.OBJLoader: Unexpected line: "' + line + '"');

            }

        }

        state.finalize();

        var container = new THREE.Group();
        container.materialLibraries = [].concat(state.materialLibraries);

        for (var i = 0, l = state.objects.length; i < l; i++) {

            var object = state.objects[i];
            var geometry = object.geometry;
            var materials = object.materials;
            var isLine = (geometry.type === 'Line');
            var isPoints = (geometry.type === 'Points');
            var hasVertexColors = false;

            // Skip o/g line declarations that did not follow with any faces
            if (geometry.vertices.length === 0) continue;

            var buffergeometry = new THREE.BufferGeometry();

            buffergeometry.setAttribute('position', new THREE.Float32BufferAttribute(geometry.vertices, 3));

            if (geometry.normals.length > 0) {

                buffergeometry.setAttribute('normal', new THREE.Float32BufferAttribute(geometry.normals, 3));

            } else {

                buffergeometry.computeVertexNormals();

            }

            if (geometry.colors.length > 0) {

                hasVertexColors = true;
                buffergeometry.setAttribute('color', new THREE.Float32BufferAttribute(geometry.colors, 3));

            }

            if (geometry.uvs.length > 0) {

                buffergeometry.setAttribute('uv', new THREE.Float32BufferAttribute(geometry.uvs, 2));

            }

            // Create materials

            var createdMaterials = [];

            for (var mi = 0, miLen = materials.length; mi < miLen; mi++) {

                var sourceMaterial = materials[mi];
                var material = undefined;

                if (this.materials !== null) {

                    material = this.materials.create(sourceMaterial.name);

                    // mtl etc. loaders probably can't create line materials correctly, copy properties to a line material.
                    if (isLine && material && !(material instanceof THREE.LineBasicMaterial)) {

                        var materialLine = new THREE.LineBasicMaterial();
                        THREE.Material.prototype.copy.call(materialLine, material);
                        materialLine.color.copy(material.color);
                        material = materialLine;

                    } else if (isPoints && material && !(material instanceof THREE.PointsMaterial)) {

                        var materialPoints = new THREE.PointsMaterial({size: 10, sizeAttenuation: false});
                        THREE.Material.prototype.copy.call(materialPoints, material);
                        materialPoints.color.copy(material.color);
                        materialPoints.map = material.map;
                        material = materialPoints;

                    }

                }

                if (!material) {

                    if (isLine) {

                        material = new THREE.LineBasicMaterial();

                    } else if (isPoints) {

                        material = new THREE.PointsMaterial({size: 1, sizeAttenuation: false});

                    } else {

                        material = new THREE.MeshPhongMaterial();

                    }

                    material.name = sourceMaterial.name;

                }

                material.flatShading = sourceMaterial.smooth ? false : true;
                material.vertexColors = hasVertexColors ? THREE.VertexColors : THREE.NoColors;

                createdMaterials.push(material);

            }

            // Create mesh

            var mesh;

            if (createdMaterials.length > 1) {

                for (var mi = 0, miLen = materials.length; mi < miLen; mi++) {

                    var sourceMaterial = materials[mi];
                    buffergeometry.addGroup(sourceMaterial.groupStart, sourceMaterial.groupCount, mi);

                }

                if (isLine) {

                    mesh = new THREE.LineSegments(buffergeometry, createdMaterials);

                } else if (isPoints) {

                    mesh = new THREE.Points(buffergeometry, createdMaterials);

                } else {

                    mesh = new THREE.Mesh(buffergeometry, createdMaterials);

                }

            } else {

                if (isLine) {

                    mesh = new THREE.LineSegments(buffergeometry, createdMaterials[0]);

                } else if (isPoints) {

                    mesh = new THREE.Points(buffergeometry, createdMaterials[0]);

                } else {

                    mesh = new THREE.Mesh(buffergeometry, createdMaterials[0]);

                }

            }

            mesh.name = object.name;

            container.add(mesh);

        }

        console.timeEnd('OBJLoader');

        return container;

    }

});

module.exports = {
    OBJLoader
};